What is the main purpose of public key encryption?

The main purpose of public key encryption is to secure data during transmission. This cryptographic method uses a pair of keys: a public key, which can be shared openly, and a private key, which is kept secret by the owner. When data is encrypted with the public key, only the corresponding private key can decrypt it, ensuring that even if the encrypted data is intercepted during transmission, it cannot be easily read by anyone who does not possess the private key.

This security mechanism is vital for protecting sensitive information, such as personal data or financial transactions, from eavesdroppers and malicious entities during online communications. Public key encryption is foundational for various secure protocols on the internet, including HTTPS, which protects web traffic, and secure email protocols, which safeguard email content.

Other options, while relevant in various contexts involving computers and networks, do not align with the primary purpose of public key encryption. The focus here is specifically on how it ensures confidentiality and integrity of data during its journey across potentially insecure channels.